388 



LABORATORY MANUAL OF HUMAN ANATOMY 



(j) Fibrocartilaginous ring (annulus fibrocartilagineus) . 

 (k) Radiate layer (stratum radiatum). 

 (1) Circular layer (stratum circulare). 

 (m) Mucous layer (stratum mucosum). 



Tympanic Mucous Membrane. 



This membrane (tunica mucosa tympanica) presents a num- 

 ber of folds and recesses. Examine 



FIG. 189. 



M. tensor tympani 



Tuba 



Memb. tymp. aitdi- 

 Meatus acusticus externus tiva 



The cavum tympani and membrana tympani. A part of the meatus acusticus externus and the 

 tuba auditiva are seen from in front, and somewhat from above and the side. (From Gegenbaur, Lehrb. 

 der Anat. des Mensch., Leipzig, 1899, 7 Aufl., Bd. II. p. 619, Fig. 730.) 



(a) Posterior malleolar fold (plica malleolaris posterior). 



(b) Anterior malleolar fold (plica malleolaris anterior). 



(c) Anterior recess of membrane of tympanum (recessus membranae 



tympani anterior). 



(d) Superior recess of membrane of tympanum (recessus membranae 



tympani superior). 



(e) Posterior recess of membrane of tympanum (recessus membranae 



tympani posterior). 



(f) Fold of anvil (plica incudis). 



(g) Fold of stirrup (plica stapedis). 



(h) Secondary membrane of tympanum (membrana tympani secundaria). 



Are any tympanic glands (Gl. tympanicae) visible? 



Auditory Ossicles. 



These small bones (ossicula auditus) are three in number, 

 stirrup (stapes], anvil (incus), and hammer (malleus). 

 In the stapes study 



(a) Head of stirrup (capitulum stapedis). 



(b) Anterior limb (crus anterius). 



